Packaging system and method for shielding brachytherapy seeds and other radiation-emitting sources

Abstract

A shielded packaging system is formed by a top panel and a bottom panel that are connected to one another along a preselected extent of their respective peripheral edges. An opening is formed along the unconnected extent and provides access to the space between the panels that holds radioactive items. Each panel includes at least two layers of lead foil so that if a pinhole is formed in either layer, the probability of two pinholes lining up and enabling radiation to escape from the space is minimal. The layers of lead foil have at least one ridge formed in them at their respective peripheral edges so that radiation traveling in a straight path parallel to the top and bottom panels encounters the ridges and cannot escape through the edges of the package.

What is claimed is:  
     
       1. A shielded packaging system formed by securing to one another a pair of abutting panels about their respective peripheries, wherein each panel comprises: 
       a first layer of plastic;  
       a first layer of lead foil;  
       a first layer of adhesive disposed between said first layer of plastic and said first layer of lead foil;  
       a second layer of lead foil;  
       a second layer of adhesive disposed between said first layer of lead foil and said second layer of lead foil;  
       a second layer of plastic;  
       a third layer of adhesive disposed between said second layer of lead foil and said second layer of plastic;  
       said layers collectively positioned in a common, substantially flat plane; and  
       said panels being joined to one another about a predetermined extent of their respective peripheral edges;  
       an opening defined where said respective peripheral edges are not joined to one another;  
       each panel of said shielded packaging system including said first and second layers of lead foil so that if a pinhole is formed in said first layer of lead foil it will not be in alignment with a pinhole that is formed in said second layer of lead foil, other than by pure chance.  
     
     
       2. The shielded packaging system of  claim 1 , wherein said respective peripheral edges of said first and second layers of lead foil of each panel are offset relative to said substantially flat plane of said packaging system so that radiation traveling in a straight line parallel to said substantially flat plane cannot escape into an ambient environment through said respective peripheral edges. 
     
     
       3. The shielded packaging system of  claim 2 , further comprising a fold formed in said shielded packaging system to close said opening, said fold being formed in said at least two layers of lead foil of each panel so that radiation traveling in a straight line parallel to said substantially flat plane cannot escape into an ambient environment through said fold. 
     
     
       4. The shielded packaging system of  claim 1 , wherein said first layer of plastic is made of a flame retardant, heat-sealable plastic. 
     
     
       5. The shielded packaging system of  claim 4 , wherein said first layer of plastic is formed of a flame retardant, beat sealable polyvinylchloride. 
     
     
       6. The shielded packaging system of  claim 4 , wherein said first layer of plastic is made of a flame retardant, heat-sealable plastic having a thickness of about 0.0035 inch. 
     
     
       7. The shielded packaging system of  claim 1 , wherein said second layer of plastic is made of a flame retardant, heat-sealable plastic. 
     
     
       8. The shielded packaging system of  claim 7 , wherein said second layer of plastic is formed of a flame retardant, heat sealable polyvinylchloride. 
     
     
       9. The shielded packaging system of  claim 1 , wherein said second layer of plastic is made of a flame retardant, heat-sealable plastic having a thickness of about 0.0035 inch. 
     
     
       10. The shielded packaging system of  claim 1 , wherein said first layer of lead foil has a thickness of at least about 0.005 inch. 
     
     
       11. The shielded packaging system of  claim 1 , wherein said second layer of lead foil has a thickness of at least about 0.005 inch. 
     
     
       12. A method for sealing radioactive items in a container, comprising the steps of: 
       providing a first layer of plastic;  
       providing a first layer of lead foil;  
       positioning a first layer of adhesive between said first layer of plastic and said first layer of lead foil;  
       providing a second layer of lead foil;  
       positioning a second layer of adhesive between said first layer of lead foil and said second layer of lead foil;  
       providing a second layer of plastic;  
       positioning a third layer of adhesive between said second layer of lead foil and said second layer of plastic;  
       positioning said layers collectively in a common, substantially flat plane to form a first panel;  
       performing the same steps to form a second panel; and  
       joining said first and second panels to one another about a predetermined extent of their respective peripheral edges so that an opening is defined where said respective peripheral edges are not joined to one another and so that if a pinhole is formed in said first layer of lead foil it will not be in alignment with a pinhole that is formed in said second layer of lead foil, other than by pure chance.  
     
     
       13. The method of  claim 12 , further comprising the step of offsetting said respective peripheral edges of said first and second layers of lead foil of each panel relative to said substantially flat plane of said packaging system so that radiation traveling in a straight line parallel to said substantially flat plane cannot escape into an ambient environment through said respective peripheral edges. 
     
     
       14. The method of  claim 13 , further comprising the step of forming a fold in said shielded packaging system to close said opening, said fold being formed in said at least two layers of lead foil of each panel so that radiation traveling in a straight line parallel to said substantially flat plane cannot escape into an ambient environment through said fold. 
     
     
       15. The method of  claim 12 , further comprising the step of making said first layer of plastic of a flame retardant, heat-sealable plastic. 
     
     
       16. The method of  claim 15 , further comprising the step of making said first layer of plastic of a flame retardant, heat sealable polyvinylchloride. 
     
     
       17. The method of  claim 12 , further comprising the step of making said second layer of plastic of a flame retardant, heat-sealable plastic. 
     
     
       18. The method of  claim 17 , further comprising the step of making said second layer of plastic of a flame retardant, heat sealable polyvinylchloride. 
     
     
       19. The method of  claim 12 , further comprising the steps of making said first layer of plastic of a plastic having a thickness of about 0.0035 inch and making said second layer of plastic of a plastic having a thickness of about 0.0035 inch. 
     
     
       20. The method of  claim 12 , further comprising the step of making said first and second layers of lead foil so that each has a thickness of at least about 0.005 inch.